Calcareous nannofossils anchor chronologies for Arctic Ocean sediments back to 500 ka

Poor age control in Pleistocene sediments of the central Arctic Ocean generates considerable uncertainty in paleoceanographic reconstructions. This problem is rooted in the perplexing magnetic polarity patterns recorded in Arctic marine sediments and the paucity of microfossils capable of providing...

Full description

Bibliographic Details
Published in:Geology
Main Authors: O’Regan, Matt, Backman, Jan, Fornaciari, Eliana, Jakobsson, Martin, West, Gabriel
Format: Article in Journal/Newspaper
Language:English
Published: The Geological Society of America 2020
Subjects:
LATE PLEISTOCENE
LOMONOSOV RIDGE
ICE
SEA
PALEOCEANOGRAPHY
BIOCHRONOLOGY
STRATIGRAPHY
Arctic
Arctic Ocean
Lomonosov Ridge
Online Access:http://hdl.handle.net/11577/3351406
https://doi.org/10.1130/G47479.1
https://pubs.geoscienceworld.org/gsa/geology/article/48/11/1115/588196/Calcareous-nannofossils-anchor-chronologies-for
Description
Summary:Poor age control in Pleistocene sediments of the central Arctic Ocean generates considerable uncertainty in paleoceanographic reconstructions. This problem is rooted in the perplexing magnetic polarity patterns recorded in Arctic marine sediments and the paucity of microfossils capable of providing calibrated biostratigraphic biohorizons or continuous oxygen isotope stratigraphies. Here, we document the occurrence of two key species of calcareous nannofossils in a single marine sediment core from the central Arctic Ocean that provide robust, globally calibrated age constraints for sediments younger than 500 ka. The key species are the coccolithophores Pseudoemiliania lacunosa, which went extinct during marine isotope stage (MIS) 12 (478–424 ka), and Emiliania huxleyi, which evolved during MIS 8 (300–243 ka). This is the first time that P. lacunosa has been described in sediments of the central Arctic Ocean. The sedimentary horizons containing these age-diagnostic species can be traced, through lithostratigraphic correlation, across more than 450 km of the inner Arctic Ocean. They provide the first unequivocal support for proposed Pleistocene chronologies of sediment from this sector of the Arctic, and they constitute a foundation for developing and testing other geochronological tools for dating Arctic marine sediments.

Similar Items